BOSTON — Former New England Patriot Aaron Hernandez, who was already accused of murder in a man's shooting death last year, "ambushed and executed" two other men a year earlier after an encounter at a nightclub, prosecutors said Thursday in announcing new murder charges against Hernandez in their deaths.

The victims in that killing, Daniel de Abreu and Safiro Furtado, were shot to death as they sat in a car in Boston's South End on July 16, 2012. Police have said they were shot by someone who drove up alongside in an SUV with Rhode Island license plates and opened fire, and Suffolk District Attorney Daniel Conley said Thursday in announcing that Hernandez has been indicted that the victims were "ambushed and executed as they drove home" and that Hernandez was the gunman.

Weeks later, Hernandez signed a five-year deal worth about $40 million with the Patriots and went on to play 12 games as a tight end for the team that season.

Lawyers for Hernandez, who is awaiting trial in the separate 2013 shooting death near his home of 27-year-old Odin Lloyd in North Attleborough, did not immediately respond to messages seeking comment about the new indictment. Hernandez is being held without bail after pleading not guilty to murder in Lloyd's death.

On the night of the 2012 attack, Hernandez and the victims encountered each other at a nightclub, Conley said, though he did not detail what happened. Hernandez was seen on surveillance footage in the nightclub that night, authorities have said.

Boston police wrote in an affidavit last year there is probable cause to believe that Hernandez was driving a vehicle used in the double shooting. The affidavit was filed as police sought to search an SUV involved in the shooting and found at Hernandez's uncle's home in Bristol, Connecticut.

The SUV was covered in dust and cobwebs and had a dead battery, leading police to believe it had remained untouched in the garage for close to a year, according to the court document.

Survivor Aquilino Freire told police an SUV pulled up next to them while they were stopped, and he saw someone in the SUV's back seat laughing, according to the affidavit. Then, several gunshots were fired from the rear passenger seat into the car, Freire told police. Two other people in the car ran away, Freire said.